I have a quick question that's probably just something I'm overlooking. I'm setting up a new web site (I've used the Metro framework since v1) and am learning all the details of v4. I've built a simple test page that uses the Appbar sample. If I change the Appbar background to a dark color and the foreground to a light color, the dropdown menu icon "disappears" (it's still dark and matches the background). Everything still functions but there's no icon to show that the menu is a dropdown.